A drum cannon comprises essentially a barrel and a drum containing several chambers. The drum is pivoted around an axis parallel to the barrel bore axis. The cartridge is pushed into the chamber, which is not in line with the barrel bore axis. Conventional bottleneck cartridges are pushed into the chamber in the aiming direction, whereas telescopic cartridges are introduced into the chamber against the aiming direction. The drum is rotated or moved until the cartridge and barrel bore axis are in line (DE 32 37 728 C2). For its part, the drum supports itself on a plate. This causes obturation problems thereby between the drum and the barrel.
These obturation problems were counteracted up to now by seal bushings between the drum and the barrel. For sealing, the seal bushing of each chamber was supported on the drum, wherein the seal bushings are moved slightly in the aiming direction. With bottleneck cartridges, the inner diameter of the seal bushing is somewhat larger than the land diameter of the barrel. During the shot, gas is guided against the face of the seal bushing in the aiming direction by means of a gas duct. Even before the seal bushing is acted upon by the gas pressure in the radial direction, the dynamic pressure pushes the opposing face of the seal bushing against the face of the barrel. This ensures a seal during the further course of the shot.
It is disadvantageous that sealing, by means of a bushing, is frequently insufficient. In particular with telescopic cartridges with combustible cases, there is the problem of guiding the gas jet onto the face of the seal bushing at the right time, before the seal bushing is impacted by gas pressure in the radial direction.
The object of the invention is to provide a seal between the drum and the barrel that seals more effectively than, for example, a bushing or the like.